         sw (q/width)
         lw (- lx fx)
         xoff (- (/ (- sw lw) 2) fx)]
-    (q/background 0)
+    (q/background 128)
     (q/fill 255 255 255)
     (q/stroke 255 255 255)
     (q/push-matrix)

    (when (:draw-frames config)
      (doseq [frame (:frames state)] (draw-frame frame)))
    (when (:draw-wings config)
      (q/fill 17 110 191)
      (q/stroke 242 237 228)
      (doseq [verts (:wings state)] (draw-verts verts)))
    (q/pop-matrix)
    (when (:draw-distortion config)

                :indent 1/3
                :sharpness 1/9}

   :distortion-intensity 60
   :distortion-xresolution 10
   :distortion-yresolution 4

   ;; presentation
   :dot-size 5
